Epigenetic and Metabolic Changes in Root-Knot Nematode-Plant Interactions

Abstract

Two wild-type field populations of root-knot nematodes (Mi-Vfield, Mj-TunC2field), and two isolates selected for virulence in laboratory on resistant tomato cultivars (SM2V, SM11C2), were used to induce a resistance reaction in tomato to the soil-borne parasites. Epigenetic and metabolic mechanisms of resistance were detected and compared with those occurring in partially or fully successful infections. The activated epigenetic mechanisms in plant resistance, as opposed to those activated in infected plants, were detected by analyzing the methylated status of total DNA, by ELISA methods, and the expression level of key genes involved in the methylation pathway, by qRT-PCR. DNA hypo-methylation and down-regulation of two methyl-transferase genes (CMT2, DRM5), characterized the only true resistant reaction obtained by inoculating the Mi-1.2-carrying resistant tomato cv Rossol with the avirulent field population Mi-Vfield. On the contrary, in the roots into which nematodes were allowed to develop and reproduce, total DNA was generally found to be hyper-methylated and methyl-transferase genes up-loaded. DNA hypo-methylation was considered to be the upstream mechanism that triggers the general gene over-expression observed in plant resistance. Gene silencing induced by nematodes may be obtained through DNA hyper-methylation and methyl-transferase gene activation. Plant resistance is also characterized by an inhibition of the anti-oxidant enzyme system and activation of the defense enzyme chitinase, as opposed to the activation of such a system and inhibition of the defense enzyme glucanase in roots infested by nematodes.

Transcriptomic and methylation analysis of susceptible and tolerant grapevine genotypes following Plasmopara viticola infection

“…In accordance with that, global methylation presented a lower increase in the tolerant genotype. Analysis of global DNA methylation pattern modification on several species after infection with different pathogens has been reported on tomato roots, Poplar bark and Arabidopsis leaves (Leonetti & Molinari, 2020 ; Xiao et al, 2021 ). Often, resistant species showed DNA hypomethylation patterns while susceptible ones presented hypermethylated DNA after pathogens attack (Leonetti & Molinari, 2020 ; Xiao et al, 2021 ).…”

“…Analysis of global DNA methylation pattern modification on several species after infection with different pathogens has been reported on tomato roots, Poplar bark and Arabidopsis leaves (Leonetti & Molinari, 2020;Xiao et al, 2021). Often, resistant species showed DNA hypomethylation patterns while susceptible ones presented hypermethylated DNA after pathogens attack (Leonetti & Molinari, 2020;Xiao et al, 2021). Also, studies have observed that altering DNA methylation levels (hypo-or hypermethylation) on genomic regions could influence gene and phenotypic responses to plant diseases (Geng et al, 2019;Leonetti & Molinari, 2020) Wang, 2015;Espinas et al, 2016;Ramirez-Prado, Piquerez, et al, 2018;Song et al, 2021;Wang et al, 2020;Zhi & Chang, 2021).…”

Mycorrhizal Association and Plant Disease Protection: New Perspectives

“…Plant stress memory is described under two categories: mitotic stress memory, or somatic memory, and meiotic stress memory, or transgenerational memory [114][115][116]. Plant stress memory associated with the inheritance of SAR is likely to be epigenetic [117,118]. In plants, defense priming and SAR are associated with epigenetic modifications of histones, DNA methylation, increased signaling enzymes, and an accumulation of pattern recognition receptors (PRRs) at cell membranes [119,120].…”

Exploiting Epigenetic Variations for Crop Disease Resistance Improvement

“…tritici (Bgt), the causal agent of wheat powdery mildew (Table 1, Geng et al, 2019). Increasing evidence revealed that DNA (de)methylation also gets involved in the regulation of plant defense response to pests and nematodes (Leonetti and Molinari, 2020). For instance, Arabidopsis mutant plants deficient in methylation of DNA and H3K9 (kyp) showed increased resistance to the infestation of green peach aphid Myzus persicae (Annacondia et al, 2021).…”